Congressional Leadership Fund, the main super PAC working to elect Republican House candidates, has launched a field program to support Republican candidates in Democratic-leaning states without competitive presidential or senate contests.

The five-year-old group, which through the previous two election cycles focused its resources on expensive television advertising, decided to make the commitment to supplement the Republican National Committee’s patchy ground operation this year.

The fund, along with American Action Network, an affiliated nonprofit group that doesn’t disclose its donors, plans to spend $2.5 million across eight districts in California, Minnesota and New York to target persuadable voters and turn others out to the polls.

Most of this year’s House battlegrounds are situated in states such as Iowa, Florida and Nevada, where the national party, state parties and Senate candidates in tight races are working to turn out voters in Republicans’ favor.

But at least 15 races are in states that are not hotly contested in the presidential election, hindering the parties’ efforts to motivate voters in other races. In its new push, the Congressional Leadership Fund will target Republicans voters and individuals who plan to vote for Hillary Clinton or a third-party candidate but could be persuaded to split their ticket.

“We knew we could be more helpful with ground troops in places that are not presidential or Senate battleground states, because there isn’t an infrastructure built out on the ground there,” said Mike Shields, Congressional Leadership Fund’s president and a former Republican National Committee chief of staff.

Democratic campaigns such as President Barack Obama’s 2012 Presidential re-election effort have demonstrated that ground operations often make better investments than large advertising campaigns. While they reach fewer voters, face-to-face conversations are considered more persuasive.

Both parties agreed that Republican ground efforts in the 2012 election were inferior to the Democrats’.
Mr. Shields said this month’s move represents the right’s growing sophistication in using reams of data to target undecided and unmotivated voters. The group, like other Republican super PACs, relies on a voter file called The Data Trust, which enables it to share its information on specific voters with other outside groups.

“We had our work cut out for us to catch up,” Mr. Shields said. “This is a sign that we’ve come a long way in building out the party data infrastructure.”

The corresponding Democratic group, House Majority PAC, does not run ground operations, preferring to focus its war chest on TV and mailed advertising. Both groups are due to report their most recent fundraising totals later this month, though Democrats have tended to raise more quarter-to-quarter this cycle.

The Democratic Congressional Campaign Committee, which is helping run virtually all ground operations in House races across the country, at work in districts in competitive battleground states. For example, the committee has helped build a turnout effort for Democrat Morgan Carroll in Republican Rep. Mike Coffman’s suburban Denver district because Mrs. Clinton’s campaign is focused on the state’s denser urban centers.

A spokesman for House Majority PAC said the group was satisfied that the House Democrats’ official campaign arm was running a sophisticated ground operation that didn’t require any supplement.